Blushing May Be Driven by Self-Awareness, New Study Suggests

Uncontrollable but foreseeable, conspicuous yet difficult to explain, blushing can feel unbearable when it accompanies humiliation, shame or plain self-consciousness.

Blushing and heightened self-awareness

New research indicates that blushing may be prompted chiefly by an intensified awareness of oneself - the sensation of being watched or exposed - rather than by a conscious assessment of what other people think.

That may be useful to understand, although the evidence comes from 40 teenage and 20-year-old participants who watched recordings of themselves singing karaoke while inside an MRI scanner. More support for a connection between blushing and self-awareness does not, however, necessarily mean that we can prevent it.

In 1872, Charles Darwin memorably called blushing "the most peculiar and most human of all expressions". It can become even stronger when somebody remarks that your face has turned crimson. Being accused of something may also bring it on, whether or not you are actually at fault.

The bodily mechanism is relatively easy to describe: blood surges towards the face, reddening the cheeks and, at times, the ears, neck, upper chest and forehead as well.

Yet the reason people blush has puzzled researchers for years. Does it stem from shame or embarrassment after an awkward error, from receiving what might be a deserved compliment, or from the feeling of being on display for everyone?

Do we turn red because we abruptly worry about others' opinions and feel judged? Or is it an automatic emotional reaction that occurs before we have had any opportunity to consider it?

What brain scans reveal about blushing

A 2004 study reported that blushing could be stronger on one side of the face than the other when a person was watched from the side while singing. However, this research and many earlier studies, including the latest one, involve samples too small to support firm conclusions.

"Whereas the pallor of fear is explicable in terms of redirection of blood flow from the skin to the skeletal muscles, it is less obvious why embarrassment over certain kinds of social predicaments should be accompanied by increased blood flow to the facial region," psychologist Ray Crozier wrote for the British Psychological Society in 2010.

For the new research, Milica Nikolic, a psychology researcher at the University of Amsterdam, and colleagues used brain scans to explore these questions. Their karaoke participants were shown footage of either themselves or other people singing.

Remarkably, only a small number of studies have charted brain-activity patterns in people induced to feel embarrassed or self-conscious. Although those studies recorded physiological signs of greater arousal, none specifically measured markers of blushing.

Nikolic and her colleagues observed that female participants' cheeks became warmer when they watched themselves sing rather than watched others, a result that is not especially surprising.

The functional MRI (fMRI) scans offered more insight. Blushing engaged brain regions linked with emotional arousal and attention, while areas associated with mentalising - imagining or reflecting on your own or another person's behavior, thoughts or intentions - were "conspicuously absent".

"These findings contribute to ongoing theoretical discussions regarding the nature of blushing and provide support for the idea that higher-order socio-cognitive processes may not be necessary for blushing to occur," Nikolic and colleagues conclude.

Limits of the blushing study

The researchers nevertheless say their findings should be "interpreted with due care", since brain-activity patterns connected with processes "as complex and pervasive as arousal, attention and mentalizing are not entirely distinct."

It also remains uncertain whether the findings will be reproduced in a larger and more varied population, rather than only among female university students. Psychology has faced the so-called replication crisis for decades, in part because of the kinds of people typically recruited as volunteers for such studies.

The study was published in Proceedings of the Royal Society B: Biological Sciences.